SilverStone SFX-L 700W Power Supply Review

Introduction and Features

Introduction

SFX form factor cases and power supplies continue grow in popularity and in market share. As one of the original manufacturers of SFX power supplies, Silverstone Technology Co. is meeting demand with new products; continuing to raise the bar in the SFX power supply arena with the introduction of their new SX700-LPT unit.

SilverStone has a long-standing reputation for providing a full line of high quality enclosures, power supplies, cooling components, and accessories for PC enthusiasts. With a continued focus on smaller physical size and support for small form-factor enthusiasts, SilverStone added the new SX700-LPT to their SFX form factor series. There are now seven power supplies in the SFX Series, ranging in output capacity from 300W to 700W. The SX700-LPT is the second SFX unit to feature a lengthened chassis. The SX700-LPT enclosure is 30mm (1.2”) longer than a standard SFX chassis, which allows using a quieter 120mm cooling fan rather than the typical 80mm fan used in most SFX power supplies.

The new SX700-LPT power supply was designed for small form factor cases but it can also be used in place of a standard ATX power supply (in small cases) with an optional mounting bracket. In addition to its small size, the SX700-LPT features high efficiency (80 Plus Platinum certified), all modular flat ribbon-style cables, and provides up to 700W of continuous DC output (750W peak). The SX700-LPT also operates in semi-fanless mode and incorporates a very quiet 120mm cooling fan.

Here is what SilverStone has to say about their new SX700-LPT power supply:

“For small form factor enthusiasts, the standard SFX power supply provides an excellent combination of size, power, and affordability. At 100mm deep, however, the standard SFX PSU is also limited in fan size to 80mm or 92mm. While advances in engineering and components have made modern high-end SFX PSUs quieter than ever, there is still inherent limitations with these fans’ ability to dissipate heat at maximum loading conditions while maintaining satisfactory noise profiles for users sensitive to higher-pitch sounds.

With this in mind, SilverStone has released a “lengthened” variation of the SFX form factor called, SFX-L. With 30mm of added depth, the SFX-L power supply has enough room to fit a 120mm fan, thus its maximum load noise can be not only lower in intensity (via slower fan speed), but also lower pitch (due to larger fan size).

The SX700-LPT marks another milestone in SilverStone’s pursuit of higher quality and more capable small form factor power supplies. At 700W, it includes all features available from top of the line SilverStone PSUs such as 80 Plus Platinum efficiency, modular flexible flat cables, all Japanese capacitors and advanced semi-fanless operation.”

First off, they clearly laid out the advantages of having a 120mm fan for lower noise.

You also lack imagination. SFX and SFX-L now make ATX sized units seem ridiculously big and unnecessary. Silverstone is coming out with a 800W 80+ Titanium rated SFX-L unit later on this year that could power an overclocked HEDT processor and dual Titan X rig easily (a lot of people over estimate the power needs for a system by a lot).

I have an R9 Nano in an SFF build which has a recommended PSU of 750W.

I bought this PSU for that build. It does just fine, even when the GPU and CPU (which is a 6600K) are both overclocked.

The 450W PSU which I had with the case originally wasn't enough for the GPU at peak load, let alone with a 95W TDP CPU + overclock. It had two 12V rails. This has one 12V rail with 58A. More than enough.

There's nothing wrong with meeting the recommended specs *and* having some additional headroom.

I would advise caution when buying this PSU do to quality control. I bought one off Amazon for my ITX build, but the PSU would randomly shut off as if the power cord was unplugged. This would happen at random times like while installing Windows, watching Youtube, or just idling. I would have to unplug the power cord from the PSU to be able to restart my PC.
I returned it and bought the SX500-LG and so far it has worked perfectly.

There's a lot of that happening, people are complaining on forums and reviews on neweeg.ca points that same issue, which is very sad. To be fair my corsair sf600 is having the same issues,It has to do with power surges.

There is a bug with the semi-fanless mode on the SX700-LPT: The fanless mode is triggered by dropping below a certain power draw only, rather than by power and/or temperature. But the unit still has overtemp protection. This means if the unit is heated up while under low-load conditions, it can become warm enough to trigger overtemp shutdown without the fan ever kicking in!
Whether this is an issue depends on PSU orientation (opening-down = bad), inlet restriction (e.g. fan filters), case airflow (if any), and ambient temperature.